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3 years ago

How to find molarity 1.mass 2. molar mass 3. volume of water added?

Chemistry

1 answer:

anyanavicka [17]3 years ago

8 0

Molarity = (numer of mole solute) / (volume of the solution)

number of mole solute = mass solute/molar mass solute

Molarity =( mass solute/molar mass solute)/ (volume of the solution)=

= ( mass solute/((molar mass solute)*(volume of the solution))

If m is a mass of the solute, M is a molar mass a solute, V is a volume of the solution (we can think as a volume of water added).

Molarity = m/(M*V)

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One of the emission lines that provides the green color in fireworks, which com s from barium salts, has a wavelength of 505nm.

PSYCHO15rus [73]

Explanation:

(a)

The relation between frequency and wavelength is shown below as:

$c=frequency\times Wavelength
$

c is the speed of light having value $3\times 10^8\ m/s$

Given, Wavelength = 505 nm

Also, 1 m = $10^{-9}$ nm

So,

Wavelength = $505\times 10^{-9}$ m

Thus, Frequency is:

$Frequency=\frac{c}{Wavelength}$

$Frequency=\frac{3\times 10^8}{505\times 10^{-9}}\ Hz$

$Frequency=5.94\times 10^{14}\ Hz$

(b)

Also, $E=\frac {h\times c}{\lambda}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

So,

$E=\frac{6.626\times 10^{-34}\times 3\times 10^8}{505\times 10^{-9}}\ J$

$E=\frac{10^{-26}\times \:19.878}{10^{-9}\times \:505}\ J$

$E=3.94\times 10^{-19}\ J$

(c)

Electromagnetic spectrum is range of the frequencies and their respective wavelengths of the various type of the electromagnetic radiation.

In order of the increasing frequency and the photon energy and the decreasing wavelength the spectrum are:

Red , Orange, Yellow, Green, Blue, Indigo, Violet

Increasing wavelength is the opposite trend. Thus, The longest visible wavelength is red and the shortest is violet.

6 0

3 years ago

Một hỗn hợp X gồm CH3OH; C2H5OH; phenol có khối lượng 28,9 gam phản ứng vừa hết với 100ml dung dịch NaOH 2M. Phần trăm theo khối

slavikrds [6]

Answer:

nNaOH = 0,2 mol

Trong hỗn hợp các chất đề bài cho chỉ có phenol tác dụng với NaOH

C6H5OH + NaOH → C6H5ONa + H2O

0,2 ← 0,2 (mol)

⟹ mphenol = 0,2.94 = 18,8 gam

⟹

%mC6H5OH=18,8/28,9 x100%= 65,05%

Explanation:

3 0

3 years ago

Each day, the stomach produces 2.0 L of gastric juice that contains 0.10 M HCl. Phillips Milk of Magnesia is a white-colored, aq

trasher [3.6K]

Answer:

It would take 72.9 mL of milk of magnesia.

Explanation:

First of all we have to think how the compounds react with each other and what are the products formed. In this case, the hydrochloric acid reacts with magnesium hydroxide to generate magnesium chloride and water as a subproduct. Having said that, we have to state the balanced chemical reaction to know the associated stoichiometry:

2 HCl + Mg(OH)2 → MgCl2 + 2 H2O

According to the balanced equation we know that 2 mol of HCl reacts with 1 mol of Mg(OH)2.

Now we calculate the quantity of moles of HCl that we have present in 2.0 lts of 0.10 M solution:

0.1 M HCl = 0.1 moles HCl / 1000 ml Solution

So, in 2 liters of solution we will have 0.2 moles of HCl

This 0.2 moles of acid, as we stated before, will react with 0.1 moles of Mg(OH)2, so we need to calculate the amount of milk of magnesia that has this required quantity of moles.

With the molar mass of Mg(OH)2 we calculate the weight of the compound that represents the 0.1 moles needed to react with all the HCl present in solution:

1 mol Mg(OH)2 = 58.32 g

0.1 mol = 5.832 g

Now we need to determine what volume of the milk of magnesia solution has 5.832 g of Mg(OH)2 to react with the acid:

The concentration of milk of magnesia is 8 % (w/v). This means that we have 8 gr of Mg(OH)2 per 100 ml of solution.

8 gr Mg(OH)2 per 100 mL Solution

5.832 gr Mg(OH)2 = 72.9 mL of Milk of Magnesia

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3 years ago

Given: h2o(aq) + h2o(l) h3o+(aq) + oh–(aq) δh°rxn > 0 when the temperature of a sample of pure water is raised above 25°c,

sesenic [268]

When Δ H > 0 that means this is an endothermic reaction, and we can assume heat as one of the reactants. SO when the temperature increases so the reaction will move rightward to decrease the reactants and increase the products and as the products increase it will make the Kw increase also as
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Methods to prevent plastic pollution

krek1111 [17]

exchange polyhene bag with jute bags as they are reuseable

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2 years ago